Imagine earning more than $9,000 every single day from a book you published 50 years ago. That’s exactly what Harper Lee earns today, and tomorrow, and will continue doing so every single day for the rest of her life. Her book “To Kill A Mockingbird” is literally the only book she has ever published in her life, but the praise and adulations it has received over the years have made it one of the best bestsellers across the world.

Since it was published, the book has grossed tens of millions of dollars in revenue, and it still continues to rack up the profits. There are more than 30 million copies of the book in circulation today. However, in spite of the humungous literary and monetary achievements of the book, there is a sweet and compelling story as to exactly why the book was written.

Nelle Harper Lee was born on April 20, 1926 in Monroeville, Alabama. As the youngest child of her family, Harper had a middle class upbringing. According to various sources, she was a voracious reader and a tomboy of sorts. By the time she had graduated from high school, she had developed an interest in English literature. Having written many long stories during her time at the college, she was already well acquainted with writing literature.

After graduating in English literature from Huntingdon College, Montgomery, Alabama, Harper decided to pursue a course in law at the University of Alabama. However, she dropped out after two years to focus on her writing career. On the suggestion of her childhood friend Truman Capote, she began submitting stories to a literary agent in New York, who later persuaded her to move to New York. She stayed in Manhattan with Michael Brown, a famous lyricist, and his wife Joy Williams, a ballet dancer.

Before she could get her stories published, she worked as an airline reservation receptionist. Naturally, she didn’t like the job and was very vocal about it with her friends.

Her real break came when she received a special Christmas gift from Michael Brown and his wife in 1956: along with receiving an entire year’s wages, there was a note attached stating “You have one year off from your job to write whatever you please. Merry Christmas.” Harper Lee knew exactly what she wanted to do: write a book.

She started writing and collecting short stories about racism in Monroeville, her hometown. Her experiences as a kid growing up in a racist society fueled most of her ideas. After finishing her short stories, she submitted them to her literary agent Michael Crain and an editor at a publishing firm called J.B. Lippincott & Co. Both the men suggested Harper that the short stories should be developed into a novel instead.

Convinced by her peers, Harper Lee spent the next two and a half years writing a book which would later come to be known as “To Kill A Mocking Bird.” The publishers warned her that the book won’t sell more than a few thousand copies, but she went ahead with the deal nevertheless. All she hoped was that “someone would like it enough to give me encouragement.”

“To Kill A Mockingbird” was finally published on July 11, 1960, though it was released under the title “Atticus.” Thankfully, Harper changed the title soon enough. The book was a great success immediately. Within a year of its publication, TKAM had been translated into 10 languages. Harper also went on to win many literary awards, including the Pulitzer Prize.

In 1962, the book was translated onto the big screen with a movie of the same name. Starring Gregory Peck and Mary Badham, and directed by Robert Mulligan, the book-based movie went on to win three Golden Globes and three Academy Awards. In the year 2003, American Film Institute even named Atticus Finch, the book’s and the movie’s protagonist, as the greatest movie hero of the 20th century.

As of today, more than 30 million TKAM books are in circulation worldwide, and it has been translated into 40 languages. The book is so popular that in 2006 British librarians rated TKAM as the book “every adult should read before they die,” even ahead of the Bible.

The book has had a profound cultural impact over the past few decades in the western world. It is so popular that it is considered required reading in most high schools in the USA. While most books released today struggle to sell even a few thousand copies, TKAM continues to sell 750,000 to 1,000,000 copies every year, which is surprising for a book which was released more than 50 years ago.

Sam Pinkus, Harper’s former book agent, allegedly mishandled her copyright license and finances. Thanks to the legal proceedings that ensued, we have precise financial data to calculate the earnings from the book.

According to the legal papers furnished against the former book agent, Harper Lee earned $1,688,064 in royalties in the first half of 2009. Assuming that the figure is an almost accurate representation of Harper Lee’s earnings from royalties, she earns almost $3,376,128 per year. That amounts to $9,249 per day; a shocking figure, especially for a book written such a long time ago.

Even after her book achieved great success, Harper chose to live a reclusive life. overwhelmed by the attention she and her book received, she stopped attending public events and being interviewed. She made an extremely rare public appearance in 2007 when she was honored with the Presidential Medal of Freedom.

Today, Harper Lee is 87-years-old and lives in a simple assisted living home in Monroeville.

As her book continues to sell at a brisk pace, the royalties keep kicking in. According to American copyright laws, the copyright owner’s heirs will continue to receive the royalties even 70 years after the death of the owner. However, having never married and with no children, Harper’s royalties will pass on to an estate set up in her name. Earning almost $4 million in royalties every year for the next 70 years doesn’t sound like a bad deal, especially when it is from a single book that was released more than five decades ago.